As akpm points out, there's really no need for generic_file_aio_read to
make a special case of count 0: just loop through nr_segs doing nothing.
And as Harvey Harrison points out, there's no need to reset retval to 0
where it's already 0.
Signed-off-by: Hugh Dickins <hugh@veritas.com>
---
Setting count (or ocount) to 0 before calling generic_segment_checks is
unnecessary too; but reluctantly I'll leave that removal to someone with
a wider range of gcc versions to hand - 4.1.2 and 4.2.1 don't warn about
it, but perhaps others do - I forget which are the warniest versions.
mm/filemap.c | 44 ++++++++++++++++++++------------------------
1 file changed, 20 insertions(+), 24 deletions(-)
--- 2.6.26-rc4/mm/filemap.c 2008-05-19 11:19:03.000000000 +0100
+++ linux/mm/filemap.c 2008-05-29 21:31:55.000000000 +0100
@@ -1199,7 +1199,6 @@ generic_file_aio_read(struct kiocb *iocb
mapping = filp->f_mapping;
inode = mapping->host;
- retval = 0;
if (!count)
goto out; /* skip atime */
size = i_size_read(inode);
@@ -1208,33 +1207,30 @@ generic_file_aio_read(struct kiocb *iocb
iov, pos, nr_segs);
if (retval > 0)
*ppos = pos + retval;
- }
- if (likely(retval != 0)) {
- file_accessed(filp);
- goto out;
+ if (retval) {
+ file_accessed(filp);
+ goto out;
+ }
}
}
- retval = 0;
- if (count) {
- for (seg = 0; seg < nr_segs; seg++) {
- read_descriptor_t desc;
-
- desc.written = 0;
- desc.arg.buf = iov[seg].iov_base;
- desc.count = iov[seg].iov_len;
- if (desc.count == 0)
- continue;
- desc.error = 0;
- do_generic_file_read(filp,ppos,&desc,file_read_actor);
- retval += desc.written;
- if (desc.error) {
- retval = retval ?: desc.error;
- break;
- }
- if (desc.count > 0)
- break;
+ for (seg = 0; seg < nr_segs; seg++) {
+ read_descriptor_t desc;
+
+ desc.written = 0;
+ desc.arg.buf = iov[seg].iov_base;
+ desc.count = iov[seg].iov_len;
+ if (desc.count == 0)
+ continue;
+ desc.error = 0;
+ do_generic_file_read(filp, ppos, &desc, file_read_actor);
+ retval += desc.written;
+ if (desc.error) {
+ retval = retval ?: desc.error;
+ break;
}
+ if (desc.count > 0)
+ break;
}
out:
return retval;
--
